Yanmar 2GM20 Started, Idled too low, won't start

[sonsets]

I am new to the forum, and to diesel engines, so I hope I am at the right place.

I recently bought a 28.5 Hunter and have had it out once. Since then (4-weeks) I have had it at the dock doing some remodeling and maintenance. Today, I decided to start the engine, and in following the recommendations I idled it back down, but apparently too far, as it died. Subsequent attempts (3 or 4) proved fruitless. I tried full throttle and no throttle and then waited 10 minutes and did a regular throttle attempt....nothing. In ever attempt I never held the starter in for more than 5 seconds.

After Googling the subject and hearing all sorts of horror stories, I figured I needed some expert advise.

Do I just need to give this a half hour, or ?????

And advice is greatly appreciated.

[Vasco]

Originally Posted by sonsets

I am new to the forum, and to diesel engines, so I hope I am at the right place.

I recently bought a 28.5 Hunter and have had it out once. Since then (4-weeks) I have had it at the dock doing some remodeling and maintenance. Today, I decided to start the engine, and in following the recommendations I idled it back down, but apparently too far, as it died. Subsequent attempts (3 or 4) proved fruitless. I tried full throttle and no throttle and then waited 10 minutes and did a regular throttle attempt....nothing. In ever attempt I never held the starter in for more than 5 seconds.

After Googling the subject and hearing all sorts of horror stories, I figured I needed some expert advise.

Do I just need to give this a half hour, or ?????



And advice is greatly appreciated.

With all that cranking and no start you need to shut the cooling water intake until the engine fires or you will fill the cylinders with water and get hydro lock.

[Jman]

Fuel filters clean? Fuel line valves on?

That's where I would start with an engine unfamiliar to me.


Sent from my iPad using Cruisers Sailing Forum

[sonsets]

Ah, that is the fear that I read about. At what point (cranking) do I need to get concerned about water in the cylinders?

[sonsets]

I just changed the filters and the fuel line was on.

[sailorchic34]

Yep change all the filters, check there is diesel in the tank. Close the raw water. after changing the fuel filter(s). first blead the air out of the filter bowl, then crack the inlet fittings at each injector.

Pull the decompresson levers, and crank for 20 seconds let the starter rest for 30 seconds and repeat for about a minute of cranking in 20 second intervals.

Tighten the injector nuts, close the decompression levers and see if the engine starts. leave the raw water is closed. You do not want the hydrolock the motor.

IF the motor does not start, repeat the bleading. It takes time and I find lots of chanting / cuss'n, to get the motor bleed. Once the motor fires, stop the motor and open the raw water to the engine. Then restart the motor.

It's a good idea to change the raw water impeller as odds are the impeller is old and has sat a while. Then you know it's good.

Also check that the banjo bolts at the lift pump and filter are tight. They can vibrate loose and let a bit O air in that way.

[sonsets]

Much appreciated, despite that I feel like I walked into a hornets nest.

Dumb question. Since this has always started immediately, and did so today, can you flood a diesel like you can a gas engine?

[four winds]

Another idea to consider, though simplistic, sometimes helps when troubleshooting.

During the four weeks you have been working on the boat, have you worked around the engine, filters, lines, etc? As in close proximity with your body or maybe parts you have been remodeling, or maybe tools.

Seems odd but consider, say a fuel line that is old and stiff but hasn't been touched or "leaned against" for ages and now is cracked and sucking air.

It's the classic it worked but now it doesn't, what changed question.


BTW, you didn't idle it down "too low" and cause it to die. If all is set and working correctly reducing speed lever to the minimum position possible results in proper idle speed.

A month ago when you ran the engine if you had to hold the speed lever off its stop to keep it running then more than likely the stop adjustment on the engine's injector pump should be checked.

[sonsets]

Ah, that is worth looking into. I was in the battery bay today and there is a fuel line running across the floor, and I could have easily stood on it.

I definitely will take a look at that tomorrow, thanks.

[four winds]

You mention new to diesels, which implies to me you may have some experience with gas engines. If so and you enjoy working on engines this little yanmar will be fun to get familiar with.

You can download a service manual by a quick googling. And if you read it in your spare time you may find that getting up to speed on diesels a simple task. That will pay you back in short order.

[sonsets]

I have downloaded the manual and have been through it once. My hurdle is that the manual is generic and not type or model specific. And then the Hunter owners manual....HA! I have seen better manuals for a tricycle.

[the_alpine]

I'm with sailor chic - air in the lines.

Bleed them well.

[four winds]

I suspect wrong manual.

Use the search phrase "yanmar 2gm20f service manual".

I have it in hard copy and pdf, factory manual with everything you need to know, including complete rebuilding of engine and trans in words and pictures. You could spends weeks studying it. File too large to attach.

The link below may be it. But I'm data throttled so can't easily download to check. It's very different from the operation manual. Hope your not the don't need a manual type. The best pros don't work without them.

http://j30.us/files/YanmarGM&HMWorkshopManual.pdf

[sonsets]

In looking over some youtubes on bleeding, one individual stated he placed a primer bulb just prior to the first fuel filter, which saved him going through the cranking process. And, it just so happens that mine too has a primer bulb in the same position.

As I stated, I am new to diesels, but am mechanically inclined. So, is his alternative a safe, easier, or perhaps both process for bleeding?

[DeepFrz]

The primer bulb will allow you to fill the filter with fuel. You still have to bleed the system before and after the high pressure pump.